mysql - distinct value combinations in sql -

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i have columns this:

value1____value2   value3____value4   value2____value1   value5____value6

is there way eliminate combination on 3rd line, since it's same { value1, value2 }?

what approach?

alter table the_table add constraint my_check unique (least(column1, column2), greatest(column1, column2))

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